Drop onto Ground 2.5?

Excalaberr · April 2, 2011, 2:07pm

My latest project requires me to place around 200 objects on a curving surface, my first thought is to use the Drop onto Ground script, however looking around 2.5 I still haven’t found it.

Is there a equivalent of Drop onto Ground in 2.5?

Thanks
Ex

liero · April 2, 2011, 4:16pm

This is a fast script that will do something like ‘Drop onto Ground’, just change ground_object_name and select your objects… it works on z axis


ground_object_name = 'Plane'

import bpy, mathutils
from mathutils import Vector
ground = bpy.data.objects[ground_object_name]
ground.select = False

for o in bpy.context.selected_objects:
    po = Vector((o.location[0],o.location[1]))
    dd = 999
    for f in ground.data.faces:
        d = po - Vector((f.center[0],f.center[1]))
        if d.length &lt; dd:
            dd = d.length
            face = f
    o.location[2] = face.center[2]

Excalaberr · April 2, 2011, 5:49pm

Thanks, thats just what I was looking for!
Ex.

liero · April 3, 2011, 8:23pm

Hi, here is a small improvement over last script, it used to work with local values, but now it will take a ground object with spatial transformations -and even modifiers like a subsurf- and place all your selected objects over the surface. It still asumes ‘gravity’ is on your z axis…


#### snap objects to ground

ground_object_name = 'Plane'

import bpy, mathutils
from mathutils import Vector
ground = bpy.data.objects[ground_object_name]
temp = ground.to_mesh(bpy.context.scene, True, 'RENDER')
temp.transform(ground.matrix_world)
ground.select = False

for ob in bpy.context.selected_objects:
    xy = Vector((ob.location[0],ob.location[1]))
    dd = 999
    for f in temp.faces:
        d = xy - Vector((f.center[0],f.center[1]))
        if d.length &lt; dd:
            dd = d.length
            face = f
    ob.location[2] = face.center[2]

and a small scene to give it a try…

Attachments

prueba_drop.blend (147 KB)

RickyBlender · April 4, 2011, 6:38am

seems to take a long time to execute like almost 10 secondes waiting then we see all object falling down on the ground

why is this so long for so few objects

nice example

liero · April 4, 2011, 7:49am

There are 400 objects in the scene that are checked against 1024 faces of the subdivided plane, that is why it takes some time… just reduce plane subdivisions. Anyway 10 seconds is faster than doing it by hand

It is a very simple script though, maybe it could be done with blender geometry module…?
And other question, how to easily traslate face normal to object rotation, ‘ob.rotation_euler = face.normal’ doesn’t seem to work…

have fun

edit: for now I will stick to: ob.rotation_euler.rotate(face.normal.to_track_quat(‘Z’,‘Y’)) to get objects rotated according to face normals… it is a oneliner but far from perfect

RickyBlender · April 4, 2011, 8:25am

normals are in or out of faces!

what do you mean translate normal ?

do you mean to get/read the face’s normal ?

liero · April 7, 2011, 2:07pm

Ricky just wanted a single line way of orienting objects according to face normal vectors, this seems to work ok in the posted blend but any help that doesn’t involve struggling with matrices is welcome


ground_object_name = 'Plane'
rotate = False

import bpy, mathutils
from mathutils import Vector
ground = bpy.data.objects[ground_object_name]
temp = ground.to_mesh(bpy.context.scene, True, 'RENDER')
temp.transform(ground.matrix_world)
ground.select = False

for ob in bpy.context.selected_objects:
    xy = Vector((ob.location[0],ob.location[1]))
    dd = 999
    for f in temp.faces:
        d = xy - Vector((f.center[0],f.center[1]))
        if d.length &lt; dd:
            dd = d.length
            face = f
    ob.location[2] = face.center[2]

    if rotate:
        ob.rotation_mode = 'QUATERNION'
        ob.rotation_quaternion = face.normal.to_track_quat('Z','Y')
        ob.rotation_mode = 'XYZ'

javierdl · May 9, 2011, 11:04pm

I need to do just that too. Except I’m not familiar enough with the scripting part of Blender
Can anyone please explain how to use this script? Unfortunately googling “Blender 2.5, how to run a script” didn’t bring me much help at all

JDL

liero · May 10, 2011, 5:15am

hi, you need a text editor window to run a script, you can modify your layout from Default to Scripting from info bar on top, or change any window to a text editor with shift+F11

so, paste the text there and edit it, change ‘Plane’ to the name of your ground object, if you want objects to orient to fit face normals set rotate to True… select your objects and press the run script button

you can also add a subsurf to the ground to get better results, then just remove it
see that I just slighty modified the script above, so run this one…

Meta-Androcto · May 10, 2011, 6:18am

hi.
http://www.pasteall.org/21504/python
drop to ground addon.
Projects page: Drop To Ground
this method may be different to the code in this thread, feel free to experiment/merge & let us know here.

javierdl · May 10, 2011, 4:34pm

Thanks a lot for the explanation Liero
Am I to do the same to use the addon, MA? Or is it different by being an addon?

JDL

buesi · October 3, 2018, 7:31pm

Thank you soooo much!

I had to change the code a little bit:

my mesh didn’t have the attribute ‘faces’ but ‘polygons’
I got an error for the part & lt ; dd: so I changed it to " < dd: "

It works for my case, but also make sure the pivot point of your objects is at the bottom, or otherwise you have to move all objects up a bit afterwards

#### snap objects to ground

ground_object_name = 'Plane'

import bpy, mathutils
from mathutils import Vector

ground = bpy.data.objects[ground_object_name]
temp = ground.to_mesh(bpy.context.scene, True, 'RENDER')
temp.transform(ground.matrix_world)
ground.select = False

for ob in bpy.context.selected_objects:
    xy = Vector((ob.location[0],ob.location[1]))
    dd = 999
    for f in temp.polygons:
        d = xy - Vector((f.center[0],f.center[1]))
        if d.length < dd:
            dd = d.length
            face = f
    ob.location[2] = face.center[2]